Barriers are used to isolate zones in a borehole to complete an operation. Some operations involve multiple spaced barriers that are sequentially deployed so that fluid at high pressures can be pumped into perforations to fracture the underground rock formation. In such applications the barriers need to redirect the pumped fluid into the perforations and complete sealing to the wellbore wall is desirable but not required. After all the intervals are sequentially treated the barriers need to be removed. Milling the barriers out is time consuming and creates the need for debris removal from the borehole.
Disintegrating materials such as controlled electrolytic materials have been used in barrier components for the purposes of minimizing or eliminating milling in some instances. Controlled electrolytic materials have been described in US Publication 2011/0136707 and related applications filed the same day. The related applications are incorporated by reference herein as though fully set forth.
Slip members referred to as barrel slips are described in U.S. Pat. No. 6,481,497 and U.S. Pat. No. 6,378,606 and are annular shapes alternatively scored longitudinally from opposing ends at spaced circumferential intervals and having multiple ramps internally to mate with a conforming shape to enlarge the diameter of the annular shape. This design had hardened inserts on an outer face that were there to penetrate the surrounding tubular for enhanced grip for the seal assembly located nearby. These barrel shapes were not intended to seal and the hardened inserts created a standoff for the annular shape keeping much of the shape away from the surrounding tubular wall to the extent that there were acceptable leak paths among the inserts that were closed off nearby with the seal assembly put in the sealing position against the surrounding tubular wall. These types of packers had to be either milled out or released in separate trips in the hole which was expensive. Such designs did not lend themselves to removal by dissolving or disintegrating as their focus was to hold differential pressures without leakage for a long period of time, such as many years.
U.S. Pat. No. 5,701,954 and U.S. Pat. No. 5,944,102 are a variation where the gripping surface is a series of serrations as opposed to small external bores where hardened inserts were affixed. In this design the serrations themselves were hardened but the basic alternating longitudinal serration design was similar.
These designs differ from the present invention where an annular structure with scores is deployed to do double duty as a seal and an anchor. Variations are contemplated where a continuous strip of sealing material can be placed on the interior and/or the exterior faces of the structure to enhance the sealing and gripping capability. Alternatively, an abutting annular shape for a seal can be placed adjacent to the scored annular shape that can do some sealing. A single ramp can be used to move both structures against the surrounding tubular. Drilled holes wider than the slots are placed at the slot ends to minimize stress concentration in that area and to prevent initiation of cracks. Another alternative is that the present invention could be manufactured from non-degradable materials. Also, the present invention could be used in combination with a conventional slip system. In this variation the present invention will only seal and the conventional slip system will grip. These and other aspects of the present invention will be more readily apparent to those skilled in the art from a review of the description of the preferred embodiment and the associated drawings while recognizing that the full scope of the invention is to be determined from the appended claims.